Association between occupational noise and vibration and anxiety in the South Korean working population: a cross-sectional study

Background Although occupational exposure to noise and vibration is common, its effect on psychological wellbeing is poorly understood. This study investigated the relationship between occupational exposure to noise and vibration and anxiety among Korean workers. Methods Data from the 5th Korean Working Conditions Survey, conducted in 2017, were used. Participants were classified into four groups according to their level of exposure, and anxiety was assessed using a self-report questionnaire. Logistic regression analysis was used to examine the significance of the association between exposure and anxiety. Results Overall, 45,241 participants were enrolled in this study. The likelihood of anxiety increased, in both males and females, when exposed to both occupational noise and vibration (males: odds ratio (OR) = 2.25, confidence interval [CI] = 1.77–2.87; females: OR = 2.17, CI = 1.79–2.61). The association between the varying degrees of noise, vibration, and combined exposure showed a dose–response relationship among males. Conclusions This study revealed that occupational noise and vibration exposure is associated with anxiety. These results suggest that more detailed regulations regarding occupational noise and vibration should be developed and implemented to ensure a safer environment for workers.

INVALIDITY OF ISOTHERMAL ANALYSIS IN ESTIMATING THE THERMAL PERFORMANCE OF STIRLING ENGINE AND CRYOCOOLER

The Stirling engine is an external heat engine, which is considered as the best option for extracting work from concentrated solar power applications. The most prominent characteristics of the engine are low noise, vibration, and emissions besides reflexivity of usage with any kind of heat source such as solar, biomass, industrial heat, etc. In the present paper, the STE-1008 gamma-type Stirling engine had been analyzed by using an isothermal model to demonstrate the failure of the model in analyzing the STE-1008 considering it firstly as an engine and secondly as a cryocooler. The energy equation had been used to demonstrate the disability of the isothermal model in achieving a successful thermal analysis for engine performance. In addition, a MATLAB code had been developed to check the credibility of the isothermal model in the estimation of the engine thermal parameters. The findings of the isothermal analysis revealed that the heat exchangers are unnecessary. But, in reality; all the necessary heat transfer occur within the heat exchangers rather than in the working space boundaries. Therefore, that is invalid conclusion. However, Schmidt's theory is capable of capturing the essential engine features superbly. In particular, it is capable of capturing the fundamental interplay between the mechanically restricted movement of the engine components as well as the thermodynamic cycle which is obtained from this theory.

Occupational Disease as the Bane of Workers’ Lives: A Study of Its Incidence in Slovakia. Part 2

The main objective of this article is to monitor the development of the number of occupational diseases related to selected physical factors in the working environment (noise, vibration and dust). Each region of Slovakia has its own specific social and economic conditions. Due to the existence of a strong correlation between the several regional variables observed, principal component analysis (PCA) was used to determine the new variables. Cluster analysis was used to group regions with similar characteristics. A dendrogram was created using the average linkage method, which illustrated the similarity of the regions studied. The value of the cophenetic correlation coefficient (CC = 0.90) confirms the validity of the average linkage method. The result of the cluster analysis is the grouping of the eight regions into five homogenic groups (clusters). An analysis of the data shows that Slovakia’s regional differences significantly influence the incidence of occupational diseases in individual regions. It is shown that, in Slovakia, the development of the number of occupational diseases has seen a favourable trend in the long term.

Door sealing mechanism and process in vehicle engineering

The reliability of door sealing plays an important role in maintaining the quality of vehicle noise, vibration, and harshness (NVH). To improve the reliability of door sealing, a novel sealing process has been proposed. The factors influencing the door sealing quality have been investigated. The relationships between the peeling force, peeling speed, and peeling time have been calculated using the five-variable rheological theory. The maximum stress versus time curve and the distribution of stress and strain at the moment of debonding have been obtained by nonlinear solid cohesive coupling dynamics simulation. The rolling process of the door sealing strip has been developed, and automatic rolling equipment for door sealing has been designed and manufactured. The factors influencing the peeling force have been determined by a peeling test of the door sealing strip. The results show that the peeling force increases with an increase in the peeling speed and time. The C-shaped structure at the front end of the base material during the stripping process makes the peeling angle sharp. In addition, the uneven stripping speed causes the stripping line to become irregular. The peeling force increases with the increase in rolling pressure and failure time. The optimum rolling pressure was 70 N/m2 and the optimum aging time was 24 h.

APPROACHES TO THE METHOD OF BUILDING A HYGIENE, SANITARY AND OCCUPATIONAL HEALTH MANAGEMENT SYSTEM

In transport, ensuring safe conditions and labor protection are of particular importance, as the lives ofpassengers and the safety of rail transport depend on the health of workers in this industry. The incidence of temporarydisability, occupational and chronic morbidity of employees of a number of transport professions have been studied.This assessment of diseases depending on age and length of service according to medical examination from thestandpoint of evidence-based medicine, which revealed the cause of increased morbidity associated with adverseworking conditions and assess the degree of its professional conditionality. It is established that the leading harmfulinfluences in the organization of work of railway transport workers are noise, vibration, nervous and emotional stressand a nuфmber of other factors. Studies have shown that prolonged and repeated exposure to factors of the productionenvironment leads to a violation of adaptive mechanisms, and their failure, contributes to pathological processes in thebody. On the basis of the conducted research the concept of interaction of object with hygiene and sanitation at theenterprise and model of integrated management of object as ecological and economic system is formulated. In theprocess of research the model of the organization of management of health of workers which organically fits into modelof conceptual balanced interaction of the enterprise with environment is developed. This model provides for the primaryprevention of diseases, both occupational and occupational, and is a tool that allows you to maintain and strengthen thehealth of workers through activities such as prevention of the causes of risk factors.

Acoustic Signature Analysis and Sound Source Localization for a Three-Phase AC Induction Motor

As part of the recent electrification of the transportation industry, internal combustion engines are being coupled with or replaced by electric motors. This movement towards an electrified drivetrain poses new noise, vibration, and harshness (NVH) challenges related to electric motors. In this paper, the acoustic signature of an electric motor was analyzed to obtain a better understanding of the sound generated by these motors. This work provides an insight into an acoustic measurement technique that can be used to identify certain frequency bands that significantly contribute to the perceived sound. In the first part, the structural response of the motor was correlated with its acoustic spectra. Furthermore, data from acoustic and structural measurements were used to analyze the order content of the signal and identify critical contributors to the overall perceived sound. The differences between data captured by microphones in different positions around the motor helped to localize components of the overall sound. The results provide some discussion about techniques to decrease the overall sound. The technique described in this paper can be extended to fan-cooled motors that are used in vehicles such as golf carts or as auxiliary motors in electric/hybrid vehicles, as well as across a wide range of industrial applications.

Dual Mass Flywheel Parameter Identification

Reducing emissions brings changes in the design of internal combustion engines and thus new challenges for dual-mass flywheels (DMF) in terms of Noise Vibration and Harshness (NVH). The first part of the article describes a simple model of a centrifugal pendulum. Consequently, a more complicated DMF dynamic model involves friction between the spring components. The second part of the article deal with the multibody model of DMF using a CAD model. The dynamic model consists of a torsion spring and two bodies. The model is compared with the experimental method, which is also described in the paper.

Features of metabolic disorders in chromium mine workers

Introduction. Working conditions, clinical and laboratory status of 236 workers of a chromium mine were investigated. Materials and methods. The observation group included 162 underground employees working in conditions of the combined impact of negative occupational factors (dust, noise, vibration, tension and severity there, cooling microclimate) - class 3.3-3.4. The comparison group included 74 mine employees working in acceptable working conditions - class 2. Results. In the observation group, the pathology of the cardiovascular and endocrine system (ICD-10: I00-I99, E00-E07) was detected 2.8-3.3 times more often (p = 0.001-0.02), the relative risk of disease formation was 2.7-3.2 times higher than in the comparison group (RR = 2.7-3.2; DI = 1.44-9.2; p = 0.001-0.02). Under the conditions of the combined effect of negative production factors, as features of metabolic disorders, it was noted that the most unfavourable - abdominal form of obesity was diagnosed 1.4 times more often (42.0%, p = 0.013), the atherogenic index was 1.2 times higher, and the level HDL is 1.2 times lower than in the comparison group (p = 0.017-0.047); “Metabolic indices” - lipid accumulation coefficient (LAP) and visceral obesity index (VAI) were 1.2-1.4 times higher than the values in the comparison group (p = 0.001-0.048). Conclusions. To implement a complex of medical and preventive measures aimed at increasing life expectancy and working longevity, early prevention of CVD, including among those working in the extraction of chrome ore, it is advisable to consider the introduction of the calculation of early markers of metabolic disorders - VAI and LAP indices in the medical examination programs.